Julian responded

You need to select 'install bootloader' to the hard disk, and then advanced options, where you can tell it to install it to /boot instead of MBR. You should have created /boot in the partitioning stage.

I assume you are using some other boot manager Julian Thomas

Thanks, Julian, that tells me what I missed.

FYI: I am not using a /boot partition, all of centos is in sdb5.

I am using grub, but it is installed into a small ~ 10 Mb grub-only partition sdb9. That chainloads all my os's, centos(sdb5), fc5(sdb6), f10(sda1) I havent been able to get f10 X working.

Jack